Abstract: A system for capture of atmospheric carbon dioxide. The system includes a carbon dioxide capture device having a capture medium operable to capture atmospheric carbon dioxide under a first set of thermodynamic conditions, and to release carbon dioxide under a second set of thermodynamic conditions different to the first set of thermodynamic conditions. The first set of thermodynamic conditions includes a first temperature range and the second set of thermodynamic conditions includes a second temperature range. A heat engine is configured receive a working fluid at an inlet temperature and arranged to discharge at least a portion of the working fluid at a discharge temperature in the second temperature range or higher, and a heat transfer arrangement is configured to convey heat from discharged working fluid to the capture medium to release carbon dioxide therefrom.

Abstract: A method of operating a gas turbine engine compressor. The method includes: determining an operating point of the compressor, and modulating mass flow of environmental control system input air to maintain the operating point of the gas turbine engine compressor within predetermined limits.

Abstract: The invention concerns an aircraft propulsion control system in which a gas turbine engine has an actuable flow opening for control of flow to or from a portion of the engine. One or more sensor is arranged to sense a condition indicative of vapor trail formation by the exhaust flow from the engine. A controller is arranged to control actuation of the flow opening so as to reduce the efficiency of the engine upon sensing of said condition by the one or more sensor. In one example, the flow opening is a variable area fan nozzle.

Abstract: A method of operating a gas turbine engine compressor. The method includes: determining an operating point of the compressor, and modulating mass flow of environmental control system input air to maintain the operating point of the gas turbine engine compressor within predetermined limits.

Abstract: The invention concerns an aircraft propulsion control system in which a gas turbine engine has an actuable flow opening for control of flow to or from a portion of the engine. One or more sensor is arranged to sense a condition indicative of vapour trail formation by the exhaust flow from the engine. A controller is arranged to control actuation of the flow opening so as to reduce the efficiency of the engine upon sensing of said condition by the one or more sensor. In one example, the flow opening is a variable area fan nozzle.